I am a British citizen married to a French citizen, living in France. We have a son of 2.5 years old who is a French citizen. We have just booked a holiday to Spain, and by booking the various bits ourselves, and by booking different bits through websites in the UK and France we have saved ourselves a fortune compared with a package from a travel agent.
However, we are having trouble finding travel insurance that will cover this kind of scenario. For example I have searched for "expat holiday insurance" and the offer I found worked fine for me, an expat but not for my wife/son because the insurer explicitly only insures people of UK/USA/Australian/NZ/Canadian nationality. I have no idea why it works like this.
Therefore, are there insurers who will cover a group of people with differing nationalities to the same level or will we need to insure ourselves separately?
I assume that recommending specific companies isn't acceptable on the Ts & Cs of the site, but if people can help with terminology that I can then search for, and any experience they have, that'd be great.
(Our flights weren't booked on the same card as the hotel, just to make matters worse!)

this kind of scenario. Is the problem that you booked through several sources (as @Rory suggested) or that travellers have different citizenships? – Vince Oct 23 '12 at 7:39